Launch JavaFX application from another class - javafx-8

Question

I need to start a javafx Application from another "container" class and call functions on the Application, but there doesn't seem to be any way of getting hold of a reference to the Application started using the Application.launch() method. Is this possible?
Thanks

Answer 1

Suppose this is our JavaFX class:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.stage.Stage;
public class OKButton extends Application {
#Override
public void start(Stage stage) {
Button btn = new Button("OK");
Scene scene = new Scene(btn, 200, 250);
stage.setTitle("OK");
stage.setScene(scene);
stage.show();
}
}
Then we may launch it from another class like this:
import javafx.application.Application;
public class Main {
public static void main(String[] args) {
Application.launch(OKButton.class, args);
}
}

Answer 2

I had the same problem as this and got round it using this hack:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import java.util.concurrent.CountDownLatch;
public class StartUpTest extends Application {
public static final CountDownLatch latch = new CountDownLatch(1);
public static StartUpTest startUpTest = null;
public static StartUpTest waitForStartUpTest() {
try {
latch.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
return startUpTest;
}
public static void setStartUpTest(StartUpTest startUpTest0) {
startUpTest = startUpTest0;
latch.countDown();
}
public StartUpTest() {
setStartUpTest(this);
}
public void printSomething() {
System.out.println("You called a method on the application");
}
#Override
public void start(Stage stage) throws Exception {
BorderPane pane = new BorderPane();
Scene scene = new Scene(pane, 500, 500);
stage.setScene(scene);
Label label = new Label("Hello");
pane.setCenter(label);
stage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
}
and then the class you are launching the application from:
public class StartUpStartUpTest {
public static void main(String[] args) {
new Thread() {
#Override
public void run() {
javafx.application.Application.launch(StartUpTest.class);
}
}.start();
StartUpTest startUpTest = StartUpTest.waitForStartUpTest();
startUpTest.printSomething();
}
}
Hope that helps you.

Answer 3

Launch JavaFX in other Class using Button:
class Main extends Application{
public void start(Stage s)throws Exception{
event();
s.show();
}
public void event(){
btn.setOnAction(new EventHandler<ActionEvent>(){
public void handle(ActionEvent ae){
Stage s = new Stage();
new SubClassName().start(s);
}
});
}
public static void main(String[] args) {
launch(args);
}
}
class SubClassName{
public void start(Stage s){
Pane pane = new Pane();
Scene addFrame = new Scene(pane,280,450);
s.setScene(addFrame);
s.show();
}
}

Answer 4

I'm not sure what you're trying to achieve, but note that you can e.g call from another class Application.launch to start the JavaFX Application thread and Platform.exit to stop it.

Answer 5

The above ways of invoking other javafx class from another sometimes work. Struggling to find an ultimate way to do this brought me to the following walk around:
Suppose this is the javafx class that exteds Application we wish to show from a different class, then we should add the following lines
class ClassToCall extends Application{
//Create a class field of type Shape preferably static...
static Stage classStage = new Stage();
#Override
public void start(Stage primaryStage){
// Assign the class's stage object to
// the method's local Stage object:
classStage = primaryStage ;
// Here comes some more code that creates a nice GUI.....
// ......
}
}
And now from the other place in the project, in order to open the window
that the above class creates do the following:
// Suppose we want to do it with a button clicked:
btn1.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
//create an object of the class you wish to invoke its
//start() method:
ClassToCall ctc = new ClassToCall();
// Then call its start() method in the following way:
ctc.start(ClassToCall.classStage);
}// End handle(ActionEvent event)
});// End anonymous class